In the last couple of weeks I've noticed a small amount of coolant under the truck after parking overnight SOMETIMES(??????). When I got under the truck to look, I noticed a couple of drops on the bottom of the starter, and the front driveshaft looks damp. The thing that's baffling me is that it doesn't happen all the time.

Where on the block above the starter could a leak be coming from? FYI, I've had to add about a cup of coolant to the rad since I noticed the first little puddle, so the leak can't be very big.

Anyone ever have something similar happen? Could it be a loose or cracked freeze plug?

<font color=blue> NEVER FORGET, NEVER FORGIVE, NEVER SURRENDER<font color=blue>

Hmm, just above the starter is the heater and its hoses, a core plug, a possible leaking head gasket (probably the least likely and hardest to fix) and just in front of it is a coolant drain plug. Some EFI models have the knock sensor screwed into the coolant drain hole. Check any of those spots for dampness.

<font color=black>HarryH3 - '75 K5</font color=black>
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Sounds to me like a freeze plug. The factory ones rust from the inside out and usually develop a pin hole leak initially. This of course is just a shot in the dark guess. There are definitely other possibilitiies.

I'd have to agree with the freeze plug diagnosis as described above, its fairly common for old plugs to leak slow at first, especially if you've ever run straight water in the system for any length of time.

I started with nothing and I still have most of that left! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>

The freeze plugs are pressed in, I usually poke a hole in the center of it, then use a rod to punch it in to the cylender sleeves at which point you can rotate it and pull it out with pliers. Given this, you may need to yank some surrounding items to get at it.

I started with nothing and I still have most of that left! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>

Just use a large socket to knock it into the coolant passage area of the block. Then grab it with a set of channel-locks and use the rounded side of the channel-locks as a pivot against the side of the block to pull it out. Now you have two options, you can get a stock type freeze plug(put sealer around it) and knock it back into the block, or you can buy one of the rubber types that you turn a nut on the outside to expand it in the hole and seal it up. By the way, if it is incredibly hard to get in there to pull the old one out of the coolant passage it won't be the end of the world if you have to leave it in there. It is common for people to do this and it doesn't cause enough of a restriction to cause any problems. Just MHO. Good luck! I have had to do this on the side of the freeway in 20 degree weather!

Given the option...yes brass ones tend to last longer. But replacement steel ones will last a long time if you remember to flush your coolant on a yearly basis (which you should do even if you have brass ones to keep scale in the radiator, heater core, water pump, and thermostat from forming). If you are the low maintainence type then the brass ones would be the way to go.

water/coolent can and does travel very easiyly. I would try to dry everything on that side to help figure out were the stuff is coming from. Do you have an overflow catch bucket? Mabie it's just coming from the blow out tube or what ever its called? Even a water pump going out on you will let coolent out of that pinhole on the bottom of your waterpump and driving the wind pushing the fluid toward the back?? Just some food for thought before you tear into your block.......

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